Before Servicing; Cassette Tape & Interface - Radio Shack 26-3501 Service Manual

4.
BEFORE SERVICING
Disassembly procedure
1
.
Remove
2 screws
(i)
and
I screws
(b).
1
From
(he sere*
sule.
leparate the
upper cabinet
item
the lower cabinet (they
are
latched togeihei
at
ihiee
points, A,
B
and
C).
Repot
ring
procodure
]
.
The
bii'-i'
of
lK«
at
jihiwetic
ftintod
board
will
be
exposed
after
the
removal
of
the
lower cabinet.
You
can check the arithmetic printed
board from
the back.
2.
Replacement
ol
the
CPU
11 is
possible.
3. If
the key primed board
is
to
be checked, the
arith-
metic
piiiilcd
buaid
lies
to be bent
at
a
right angle
alter
removing
the screws
)d)
anc
(el.
Inspection
ol
the
CPU
1
b
possible
if
the bizzrr
Is
removed
after
lemming
sciew(c).
4.
The hey printed
bontd can
be dismounted by removing 9 gcrrws
(f>
and
1 screws
<$>
Tale
care as
you remove
rtie
printed
board, so y«
.
i
ilonl
*plll
i
In*
he/
lops.
LkcI
Replacement
of the LSI
1
.
Only
« very fine
soldering pencil
should be
used tot
replacing
the LSI.
2.
Be
sure to first
remove
the
key primed board
fiotn the
uppei
cabinet.
If
the
LSI
on
the
key primed boird
is
to
be
removed,
if
the LSI
s removed while the
key ptlnted
board
Is
on
the
upper cibinci. there
is
a
poistbUity
of deforming
the
key
rubber with Ute heal of
the wittering pencil.
?.
Bcsurc tocut each pinof
the
defeciive
K.
a -
Measuring
current
consumption
tVwer source
volnge 4.72V
Cuitem consumption:
After pressing the
(IN key Under
ftSQuA
After
pressing the
OFF
key: Under
1
2(iA
5.
CASSETTE TAPE &
INTERFACE
For
details
of
operation
and connection,
refer
to
-Jie
Owner's Manual
for the
TRS-80
Pocket
Computer
.
Notes
on
suitable recorders
While
Radio
Slack's
CTK-SOA
is
the intended
cassette Recorder, oiheri
can
b*
used The
following totes
1.
Cassettes oi
upciMecl tjpci can te used.
2.
Mic input jack
must lia« an
oipui
impedance of
IK
or
leas,
wiih
a
sensitivity
level
of
at
least
-tmV.
3.
Eaiphone output must Hjvb an output
impedance of
I
OK
or
less
and an outpu:
level
nf
1
volt
or
more.
4.
Allowable
distortion
is
-1 %%. *ith frequency
response from
?
to
4k
H?
wy
Im> hclpl'ii
14